A sealed gas syringe contains a mixture of nitrogen dioxide (NO2\text{NO}_2NO2, a brown gas) and dinitrogen tetroxide (N2O4\text{N}_2\text{O}_4N2O4, a colourless gas). The system is allowed to reach dynamic equilibrium.
Explain why the intensity of the brown colour in the syringe remains constant once equilibrium has been established.
60 exam-style questions on Edexcel GCSE Chemistry 6.3 Dynamic equilibria, covering 6.3.1 The Haber process as a reversible reaction, 6.3.2 Conditions and rate in industrial equilibria, and 6.3.3 Fertilisers and the preparation of ammonium sulfate. Each one has a worked solution and a mark scheme showing where the marks go.